Intermittent Moderate Energy Restriction Improves Weight Loss Efficiency in Diet-Induced Obese Mice

Abstract

BackgroundIntermittent severe energy restriction is popular for weight management. To investigate whether intermittent moderate energy restriction may improve this approach by enhancing weight loss efficiency, we conducted a study in mice, where energy intake can be controlled.MethodsMale C57/Bl6 mice that had been rendered obese by an ad libitum diet high in fat and sugar for 22 weeks were then fed one of two energy-restricted normal chow diets for a 12-week weight loss phase. The continuous diet (CD) provided 82% of the energy intake of age-matched ad libitum chow-fed controls. The intermittent diet (ID) provided cycles of 82% of control intake for 5–6 consecutive days, and ad libitum intake for 1–3 days. Weight loss efficiency during this phase was calculated as (total weight change) ÷ [(total energy intake of mice on CD or ID)–(total average energy intake of controls)]. Subsets of mice then underwent a 3-week weight regain phase involving ad libitum re-feeding.ResultsMice on the ID showed transient hyperphagia relative to controls during each 1–3-day ad libitum feeding period, and overall ate significantly more than CD mice (91.1±1.0 versus 82.2±0.5% of control intake respectively, n = 10, P<0.05). There were no significant differences between CD and ID groups at the end of the weight loss or weight regain phases with respect to body weight, fat mass, circulating glucose or insulin concentrations, or the insulin resistance index. Weight loss efficiency was significantly greater with ID than with CD (0.042±0.007 versus 0.018±0.001 g/kJ, n = 10, P<0.01). Mice on the CD exhibited significantly greater hypothalamic mRNA expression of proopiomelanocortin (POMC) relative to ID and control mice, with no differences in neuropeptide Y or agouti-related peptide mRNA expression between energy-restricted groups.ConclusionIntermittent moderate energy restriction may offer an advantage over continuous moderate energy restriction, because it induces significantly greater weight loss relative to energy deficit in mice.

Meal pattern alterations associated with intermittent fasting for weight loss are normalized after high-fat diet re-feeding

“…The major finding that there were no residual effects on meal patterns following weight restoration suggests that the effects on eating are transient. In addition, we anticipate that neural and metabolic effects previously characterized by our lab and others [24][25][26][27] are lost with weight restoration, but this remains to be determined with future experiments. +++ indicates difference from IMF-HFD (P < 0.001).…”

“…Even though there were no differences in body weight between the groups on day 78, after 49 days on re-feeding of HFD, one possibility is that the PF groups had a different trajectory of restoration of body composition compared with the other diet groups. A previous study by Seimon and colleagues [27] examined weight regain following weight loss in DIO C57BL/6 mice with intermittent diet (cycled ~18% calorie restriction for 5-6 days) and restricted continuous (~18 %) diet. During the weight regain phase (3 weeks) mice were re-fed chow and despite no differences in body weight between the groups, the two previously DIO groups exposed to an intermittent diet or continuous restriction had higher fat mass than the lean ("never obese") chow-fed controls [27].…”

“…A previous study by Seimon and colleagues [27] examined weight regain following weight loss in DIO C57BL/6 mice with intermittent diet (cycled ~18% calorie restriction for 5-6 days) and restricted continuous (~18 %) diet. During the weight regain phase (3 weeks) mice were re-fed chow and despite no differences in body weight between the groups, the two previously DIO groups exposed to an intermittent diet or continuous restriction had higher fat mass than the lean ("never obese") chow-fed controls [27]. Moreover, the intermittent diet group had increased epididymal fat compared with the lean chow-fed groups after weight regain, an effect that was not observed in the continuously restricted group [27].…”

“…The notion that prolonged CR or IMF protocols contribute to eating pathologies, however, has not been supported by clinical studies [22,23]. Nonetheless, several rodent studies have indicated alterations in the neural and metabolic controls of body weight homeostasis with IMF or prolonged CR for weight loss [24][25][26][27]. One missing component to our understanding is the acute and long-term influence of calorie restricted dietary strategies on eating behaviors.…”

Time-restricted feeding of a high-fat diet in male C57BL/6 mice reduces adiposity but does not protect against increased systemic inflammation

“…The formula for the homeostatic model of insulin resistance (HOMA-IR) was used for this (Seimon et al 2016).…”